JP5757222B2 - Submersion method for reactor containment - Google Patents

Description

  The present invention relates to a method for flooding a containment vessel.

  When a severe accident occurs that damages or melts the reactor pressure vessel or the nuclear fuel in it, it is necessary to repair or remove them. In such a state, the inside of the reactor containment vessel has a very high radiation dose. In other words, it is not easy to access the reactor pressure vessel or the reactor containment vessel. For this reason, it is assumed that the reactor containment vessel is submerged and the work is performed after reducing the radiation dose.

  In a boiling water reactor called MARK-I or an improved MARK-I (see, for example, Patent Document 1), a containment vessel includes a dry well that houses a reactor pressure vessel, and a suppression in which a pool is formed. The chamber includes a vent pipe connecting the dry well and the suppression chamber. When such a severe accident occurs in such a boiling water reactor, the reactor containment vessel is submerged for operation.

JP-A-4-348299

  However, if a part of the suppression chamber or vent pipe is damaged, the supplied water will not be discharged from the reactor containment vessel via the damaged part of the suppression chamber or vent pipe even if water is poured into the dry well. To leak. For this reason, it may be difficult to flood the reactor containment vessel.

If the state of the damaged part can be analyzed and specified in detail, water leakage can be prevented by repairing only the damaged part. However, it is difficult to analyze and specify the state of such a damaged portion in detail over a wide range under a high radiation dose.
It is also conceivable to prevent leakage of water without specifying a damaged part by closing all the torus chambers in which the suppression chambers are stored with a water-stopping material such as concrete. However, in such a case, a large amount of concrete is required. Since these concretes are contaminated with radioactive materials, it is necessary to perform appropriate treatment from the flooding of the reactor containment vessel to after the repair and nuclear fuel removal operations are completed. That is, when all the torus chambers are closed with a water-stopping material such as concrete, a large amount of radioactive waste is generated.

  The present invention has been made in view of the above-described problems, and is a method for flooding a reactor containment vessel in which at least one of a suppression chamber and a vent pipe is likely to have a damaged portion, and the reactor containment vessel The purpose is to submerge the reactor containment vessel while minimizing the amount of water-stopping material and water required for flooding.

  The present invention adopts the following configuration as means for solving the above-described problems.

  1st invention has a dry well which accommodates a reactor pressure vessel, a suppression chamber provided in the circumference of the dry well, and a vent pipe which connects the dry well and the suppression chamber, The suppression chamber Alternatively, it is a flooding method for a containment vessel having a damaged portion that causes water leakage in any one of the vent pipes, and it is determined whether a water stopping material supply path for supplying the water stopping material to the vent pipe can be secured. And a vent pipe closing step for filling the water stop material into the vent pipe when it is determined that the water stop material supply path can be secured in the path determination step. A configuration is adopted in which a water supply step of supplying water to the reactor containment vessel is performed after the step.

  According to a second invention, in the first invention, a downcomer is provided below the vent pipe to connect the internal space of the suppression chamber and the vent pipe. When it is determined that the supply path cannot be secured, a filling confirmation step for determining whether the water stop material can be filled in the suppression chamber, and the water stop material is filled in the suppression chamber in the filling confirmation step. A downcomer blockage step of filling the suppression chamber with the water-stopping material until the downcoma opening is closed, and the water supply step is performed after the downcoma blockage step. adopt.

  A third invention is the above-mentioned second invention, wherein a torus chamber in which the suppression chamber is installed is provided, and it is determined in the filling confirmation step that the water stop material cannot be filled in the suppression chamber. The torus chamber has a torus chamber closing step for filling the water stop material to the height of the connection portion between the suppression chamber and the vent pipe, and the water supply step is performed after the torus chamber closing step. Is adopted.

  A fourth invention is the above-mentioned third invention, wherein a vacuum breaker for connecting the suppression chamber and the vent pipe is provided, and when the damaged part is confirmed in the vacuum breaker, the torus The structure which fills the said water stop material to the height of the broken location of the said vacuum breaker in a chamber closing process is employ | adopted.

According to the first aspect of the present invention, when the water stop material supply path for supplying the water stop material to the vent pipe can be secured, the vent pipe is closed by filling the vent pipe with the water stop material. In this way, all (eight) vent pipes are blocked by the water stop material, so that it is possible to prevent water from flowing out through the vent pipe when the reactor containment vessel is submerged. According to the first invention as described above, the amount of the water stop material is only the amount supplied into the vent pipe, and can be extremely reduced as compared with the case where the water stop material is filled in the entire torus chamber. . In addition, according to the first invention, since the vent pipe is closed, the dry well can be submerged without accumulating water in the suppression chamber, and the water can be filled more than when the reactor containment vessel is completely filled with water. The amount of can be reduced.
Therefore, according to the first aspect of the present invention, there is provided a method for flooding a containment vessel in which there is a high possibility that a damaged portion is present in either the suppression chamber or the vent pipe, and is necessary for flooding the reactor containment vessel. The containment vessel can be submerged while suppressing the amount of water and water as much as possible.

Further, according to the second invention, although the water stop material supply path cannot be secured, when the water stop material can be filled in the suppression chamber, the opening of the downcomer connected below the vent pipe is blocked. A water stop material is supplied into the suppression chamber to close the downcomer opening. In this way, the opening of the downcomer that connects the internal space of the suppression chamber and the vent pipe is blocked, thereby preventing water from flowing into the suppression chamber via the vent pipe when the reactor containment vessel is submerged. can do. According to the second aspect of the invention, the amount of the water-stopping material is the amount from the bottom of the suppression chamber to the height at which the opening of the downcomer is closed, compared with the case where the torus chamber is closed with the water-stopping material. Can be reduced. Further, according to the second invention, since the opening of the downcomer is closed, the dry well can be submerged without accumulating water in the suppression chamber, and the water can be filled more than when the reactor containment vessel is completely filled with water. The amount of can be reduced.
Therefore, according to the second aspect of the present invention, there is a method in which a damaged portion is present in the suppression chamber, the location can be specified, and the reactor containment vessel can be submerged without repair. The reactor containment vessel can be flooded while suppressing the amount of water-stopping material and water necessary for flooding the containment vessel as much as possible.

  Further, according to the third invention, when the water stop material supply path cannot be secured and the water stop material cannot be filled in the suppression chamber, the water stop material is filled in the torus chamber where the suppression chamber is installed. Close the torus room. By closing the torus chamber in this way, it is possible to prevent water from leaking out of the suppression chamber when the reactor containment vessel is submerged even when the vent pipe is damaged. According to the third aspect of the invention, the amount of the water-stopping material is a height up to the height at which the connection portion between the vent pipe and the suppression chamber is embedded, and compared with the case where the entire torus chamber is closed with the water-stopping material. Can be reduced.

  Further, according to the fourth aspect of the invention, even when the vacuum breaker disposed above the connection portion between the vent pipe and the suppression chamber is damaged, when the reactor containment vessel is submerged, It is possible to prevent leakage to the outside of the suppression chamber. According to such 4th invention, the quantity of a water stop material becomes a part to the height which embeds the damage location of a vacuum breaker, and decreases compared with the case where all the torus chambers are plugged up with a water stop material. be able to.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view showing a schematic configuration of a boiling water reactor including a reactor containment vessel that is submerged by a method of flooding a reactor containment vessel according to a first embodiment of the present invention. It is AA sectional drawing of FIG. It is a flowchart for demonstrating the flooding method of the reactor containment vessel which is one Embodiment of this invention. It is a flowchart for demonstrating the process of supplying a filler to a suppression chamber in the flooding method of the reactor containment vessel which is 1st Embodiment of this invention. It is a schematic diagram for demonstrating the flooding method of the nuclear reactor containment vessel which is 1st Embodiment of this invention. It is a schematic diagram for demonstrating the flooding method of the nuclear reactor containment vessel which is 1st Embodiment of this invention. It is a schematic diagram for demonstrating the flooding method of the nuclear reactor containment vessel which is 1st Embodiment of this invention. It is a schematic diagram for demonstrating the flooding method of the nuclear reactor containment vessel which is 1st Embodiment of this invention. It is a schematic diagram for demonstrating the flooding method of the nuclear reactor containment vessel which is 1st Embodiment of this invention. It is a schematic diagram for demonstrating the flooding method of the nuclear reactor containment vessel which is 1st Embodiment of this invention. It is a flowchart for demonstrating the process of supplying a filler to a suppression chamber in the flooding method of the reactor containment vessel which is 2nd Embodiment of this invention.

  Hereinafter, an embodiment of a method for flooding a containment vessel according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size. Moreover, in the following description, the example which applied this invention to the method of flooding the MARK-I type | mold reactor containment vessel which is one of the boiling water reactors is demonstrated. The present invention is not limited to the MARK-I type, and can be applied to a method of flooding a MARK-I modified reactor containment vessel.

(First embodiment)
First, the MARK-I type boiling water reactor 1 will be described. FIG. 1 is a longitudinal sectional view showing a schematic configuration of a MARK-I type boiling water reactor 1. FIG. 2 is a cross-sectional view taken along the line AA in FIG. In FIG. 2, a reactor building 2 described later is omitted. As shown in FIG. 1, the MARK-I type boiling water reactor 1 includes a reactor building 2, a reactor containment vessel 3, a vent header 4, a downcomer 5, a support 6, and a reactor pressure. A container 7 and a core (not shown) are provided.

  The reactor building 2 is a building that houses a reactor containment vessel 3, a vent header 4, a downcomer 5, a support portion 6, a reactor pressure vessel 7, and a core (not shown), and is formed of reinforced concrete. ing. A torus chamber 2a for installing a suppression chamber 3b of a reactor containment vessel 3 to be described later is provided at the lower part of the reactor building 2. Although not shown, the reactor building 2 also stores an emergency core cooling system pump, a purification facility, a fuel pool, an equipment temporary storage pool, an emergency gas processing system facility, and the like.

  The reactor containment vessel 3 includes a dry well 3a that accommodates the reactor pressure vessel, a suppression chamber 3b that is provided around the dry well 3a, and a vent pipe 3c that connects the dry well 3a and the suppression chamber 3b. ing.

  The dry well 3 a is a steel container having a round bottom flask shape, and is installed in the inner wall of the reactor building 2. The suppression chamber 3b is a steel container whose cross-sectional shape is circular as shown in FIG. 1 and whose plan view shape is a polygonal annular shape as shown in FIG. If the suppression chamber 3b is not damaged due to a severe accident, water is stored inside the suppression chamber 3b to form a pool. The vent pipe 3c is provided between the dry well 3a and the suppression chamber 3b, and is a steel pipe that guides the steam to the suppression chamber 3b when the steam leaks into the dry well 3a. As shown in FIG. 2, eight vent pipes 3c are provided. The vent pipes 3c are arranged at equal intervals.

  The vent header 4 is an annular tube disposed concentrically with the suppression chamber 3b inside the suppression chamber 3b. The vent header 4 is connected to the tips of all the vent pipes 3c.

  The downcomer 5 is attached to the vent header 4 connected to the vent pipe 3c. The downcomer 5 is an inverted U-shaped tube member, and has openings 5 a at both ends facing downward, and the top is connected to the vent header 4. In addition, when the pool is formed in the inside of the suppression chamber 3b, the opening 5a of the downcomer 5 is arrange | positioned under the water surface of this pool. Via the downcomer 5, the internal space of the suppression chamber 3b and the vent pipe 3c are connected. As shown in FIG. 2, a plurality of such downcomers 5 are provided along the vent header 4 at equal intervals.

  The support 6 is a reinforced concrete member provided at the bottom of the dry well 3 a and supports the reactor pressure vessel 7. The reactor pressure vessel 7 is fixed on the support portion 6 and disposed inside the dry well 3a. The reactor pressure vessel 7 is a steel vessel and houses a reactor core therein. The core (not shown) is constituted by nuclear fuel and control rods, and is supported inside the reactor pressure vessel 7.

  Next, the flooding method of the reactor containment vessel 3 of this embodiment will be described with reference to the flowchart of FIG. In addition, the flooding method of the containment vessel 3 of the present embodiment is for filling the interior of the dry well 3a with water from a state in which the vent pipe 3c or the suppression chamber 3b is damaged due to a severe accident. Do. Moreover, at the time of starting the flooding method for the reactor containment vessel 3 of the present embodiment, the cooling water is continuously supplied to the reactor pressure vessel 7, and at least a part of the supplied cooling water is at least dry well. 3a and the suppression chamber 3b. Further, it is assumed that the supply of cooling water to the reactor pressure vessel 7 is continued at the time when the flooding method for the reactor containment vessel 3 of the present embodiment is started. Further, it is assumed that cooling water leaks from the reactor pressure vessel 7.

  First, as shown in FIG. 3, it is determined whether or not the filling material injection method in the vent pipe is possible (step S1). As described above, various devices such as an emergency core cooling system pump, a purification facility, a fuel pool, an equipment temporary storage pool, and an emergency gas processing system facility are installed in the reactor building 2. For this reason, when judging whether the filling material injection method in the vent pipe is possible, avoiding these devices, supplying the filling material for supplying the filling material (water-stopping material) to all the vent pipes 3c. It is determined whether a route (supply pipe 21 shown in FIG. 5B) can be secured. Then, when the filler supply path can be secured, it is determined that the filling material injection method in the vent pipe is possible. Note that such a step S1 determines whether or not a filler supply path (water stop material supply path) for supplying the filler 11 (water stop material) as shown in FIG. 5B to the vent pipe 3c can be secured. And corresponds to the route determination step in the present invention.

  If it is determined in step S1 that the filling material injection method in the vent pipe is possible, the filling material 11 is injected into the vent pipe 3c (step S2). In this step S2, for example, as shown in the schematic diagram of FIG. 5 (a), a room that is provided in the reactor building 2 and is located on the upper floor of the torus room 2a (hereinafter referred to as the upper floor room 2b). Therefore, the backup material 10 is arranged in the vent pipe 3c through the supply pipe 20 of the backup material 10 with respect to each vent pipe 3c. This backup material 10 is for preventing the filler 11 from flowing out. Subsequently, as shown in FIG. 5 (b), the supply pipe 21 (filler supply path) of the filler 11 is passed from the upper floor chamber 2 b to each vent pipe 3 c, and is drywelled more than the backup material 10. Filler 11 is injected into the 3a side. As the filler 11, for example, a water-stopping material that solidifies after elapse of a certain time, such as concrete, or a water-stopping material made of polymer gel, water glass, or the like can be used.

  And all the vent pipes 3c are filled with the filler 11, whereby the vent pipes 3c are closed. Note that such step S2 is a step of filling the filler 11 into the vent pipe 3c when it is determined in step S1 that the filler supply path (supply pipe 21) can be secured. This corresponds to the closing process. By closing all the vent pipes 3c in this manner, the reactor containment vessel 3 can be filled with water (step S8).

  If it is determined in step S1 that the vent pipe filling material injection method cannot be performed, it is determined whether the filling material 11 is possible in the suppression chamber 3b up to the lower end of the downcomer 5 (that is, the opening 5a). (Step S3). In this step S3, for example, as shown in FIG. 6A, the water level gauges 31 and 32 are installed for the dry well 3a and the suppression chamber 3b. Thereafter, as shown in FIG. 6B, a perforation is formed in the vicinity of the vent pipe 3c from the upper floor chamber 2b via the torus chamber 2a, and a CCD camera or the like capable of remotely operating the outside of the vent pipe 3c from this perforation. And confirm whether there is a broken portion in the vent pipe 3c or the connection portion between the vent pipe 3c and the dry well 3a. In addition, the drainage path 23 of the torus chamber 2a is formed as needed.

  If there is no breakage in the vent pipe 3c or the connection portion between the vent pipe 3c and the dry well 3a, it is determined that the filler 11 can be filled up to the lower end of the downcomer 5. Further, if there is a broken portion at the connection portion between the vent pipe 3c or the vent pipe 3c and the dry well 3a, it is determined that the filler 11 cannot be filled up to the lower end of the downcomer 5.

  When it is determined in step S3 that the filler 11 can be filled up to the lower end of the downcomer 5 in the suppression chamber 3b, it is confirmed whether there is a portion where the filler 11 leaks in the lower part of the suppression chamber 3b. (Step S4). This confirmation is performed by, for example, photographing with the above-described CCD camera or the like that can be operated remotely. If it is confirmed that there is a leak point in the lower part of the suppression chamber 3b, can the filler 11 be filled to the lower end of the downcomer 5 by continuing to fill the filler 11 even in this case? Is determined (step S5). If the sealing property in the torus chamber 2a is ensured up to the height of the damaged portion, the filler 11 can be filled up to the lower end of the downcomer 5 even if the lower portion of the suppression chamber 3b is damaged. For this reason, for example, it is determined whether the filler 11 can be continuously filled by confirming the sealing property in the torus chamber 2a.

  By these step S3 to step S5, it is determined whether or not the filler 11 can be finally filled in the suppression chamber 3b. That is, such steps S3 to S5 are steps for determining whether or not the filler 11 can be filled into the suppression chamber 3b when it is determined in step S1 that the vent pipe filler injection method cannot be performed. This corresponds to the filling confirmation process.

  When it is determined that the filler 11 can be filled into the suppression chamber 3b (that is, when it is determined that the filler 11 can be filled up to the lower end of the downcomer 5 in step S3, the filler 11 is placed below the suppression chamber 3b in step S4. When it is determined that there is no leaking portion, or when it is determined that the filler 11 can be continuously filled in step S5), the filler 11 is filled to a height exceeding the lower end of the downcomer 5. (Step S6).

  Here, the procedure for filling the filler 11 to the lower end of the downcomer 5 will be described with reference to the flowchart of FIG. 4 and FIGS. Here, the case where it is determined in step S3 that the filler 11 can be filled up to the lower end of the downcomer 5 will be described as an example.

First, as shown in FIG. 7A, a water circulation path 24 including the suppression chamber 3b and the reactor pressure vessel 7 is formed (step S11). In the middle of the circulation path 24, a purifier 25 for removing radioactive substances and a heat exchanger 26 for cooling water are installed. Moreover, the above-mentioned water level gauges 31 and 32 are also installed.
Subsequently, it is determined whether decontamination of the suppression chamber 3b and the torus chamber 2a is necessary (step S12). If it is determined that decontamination is necessary, the drainage path 27 for discharging water from the torus chamber 2a and the suppression chamber 3b and the decontamination for performing decontamination within the torus chamber 2a and the suppression chamber 3b. The dyeing path 28 is formed (see FIGS. 7B and 8A).
And as shown in FIG.7 (b), the water in the suppression chamber 3b is drained using the drainage path 27 in the state which stopped the circulation of the water in the circulation path 24 (step S13). At this time, a circulation path capable of pouring water from the external purification system to the reactor pressure vessel 7 is formed and water is poured, and the water level in the dry well 3a is set to a level at which the cooling water does not flow into the vent pipe 3c. Further, as shown in FIG. 8A, using the decontamination path 28, the torus chamber 2a and the suppression chamber 3b are decontaminated, for example, by high pressure spraying (step S14). At this time, the circulation path 24 is connected to the lower part of the dry well 30 from the suppression chamber 3b to restart the water circulation, and the connection state of the water level gauge 31 is changed so that a higher water level can be measured. In addition, the waste water generated by the decontamination in the torus chamber 2a and the suppression chamber 3b is drained to the outside through the drain path 27.

  Subsequently, the filler 11 is filled into the suppression chamber 3b (step S15). Here, as shown in FIG. 8B, a filler supply path 29 is formed instead of the decontamination path 28, and the filler 11 is supplied from the filler supply path 29 into the suppression chamber 3b. And supply of the filler 11 is continued until it exceeds the opening 5a of the downcomer 5. In addition, since water may remain in the suppression chamber 3b, the drainage using the drainage path 27 is continued. As a result, the opening 5a of the downcomer 5 is closed.

  If it is determined in step S12 that decontamination is not necessary, it is determined whether the filler 11 can be used in water (step S16). Here, being usable in water means that water can be stopped by supplying the filler 11 into water. If it is determined that the filler 11 cannot be used in the water, the suppression chamber 3b (if necessary, the torus chamber 2a) is drained (step S17), and then the step 11 is performed to fill the filler 11. To do.

  When it is determined in step S16 that the filler 11 can be used in water, the filler 11 is filled in the suppression chamber 3b without draining the suppression chamber 3b (step S19). Thereafter, the drainage is repeated until there is no water in the suppression chamber 3b (step S19 and step S20).

  Returning to FIG. 3, when it is determined that the filler 11 cannot be filled into the suppression chamber 3b (that is, when it is determined in step S3 that the filler 11 cannot be filled up to the lower end of the downcomer 5, or the filling is continued in step S5). If it is determined that the material 11 cannot be filled), the torus chamber 2a is filled with the filler 11 (step S7). Here, as shown in FIG. 9A, the filling material 11 is filled until at least the connection portion between the vent pipe 3c and the suppression chamber 3b is buried (in the present embodiment, all of the suppression chamber 3b is buried). To do. Here, the filling amount of the filler 11 is set so as not to reach the ceiling of the torus chamber 2a. In step S7, when it is determined that the filling material 11 cannot be filled into the suppression chamber 3b, the filling material 11 is filled in the torus chamber 2a up to the height of the connection portion between the suppression chamber 3b and the vent pipe 3c. This process corresponds to the torus chamber closing process of the present invention.

  In addition, as shown in FIG.9 (b), when the vacuum breaker 8 which connects the suppression chamber 3b and the vent pipe 3c is arrange | positioned upwards rather than the connection site | part of the suppression chamber 3b and the vent pipe 3c. Confirms whether or not the vacuum breaker 8 is damaged. When it is determined that the vacuum breaker 8 is damaged, the torus chamber 2a is filled with the filler 11 up to a height at which the damaged portion of the vacuum breaker 8 is buried. Here again, the filling amount of the filler 11 is set so as not to reach the ceiling of the torus chamber 2a.

  Then, step S2 (filling of the filler 11 into the vent pipe 3c), step S6 (filling of the filler 11 to a height exceeding the lower end of the downcomer 5) or step S7 (filling of the filler 11 into the torus chamber 2a). Is completed, the dry well 3a of the reactor containment vessel 3 is filled with water (step S8). For example, when the interior of the dry well 3a is filled with water from the state shown in FIG. 8B, the amount of cooling water supplied from the outside to the reactor pressure vessel 7 is continued as shown in FIG. 10A. When the dry well 3 a is submerged, the cooling water supply from the outside to the reactor pressure vessel 7 is stopped and the water is circulated through the circulation path 24. Such step S8 is a step of supplying water to the reactor containment vessel 3 in order to flood the reactor containment vessel 3, and corresponds to the water supply step of the present invention.

According to the flooding method of the reactor containment vessel 3 of the present embodiment as described above, when the filler supply path (supply pipe 21) for supplying the filler 11 to the vent pipe 3c can be secured, the vent pipe 3c is filled. By filling the material 11, the vent pipe 3c is closed. Thus, when the vent pipe 3c is blocked by the filler 11, it is possible to prevent water from flowing out through the vent pipe 3c when the reactor containment vessel 3 is submerged. According to the flooding method of the reactor containment vessel 3 of this embodiment, the amount of the filler 11 is only the amount supplied into the vent pipe 3c, and the torus chamber 2a is completely filled with the filler 11. It can be very little compared with. Moreover, according to the flooding method of the reactor containment vessel 3 of this embodiment, since the vent pipe 3c is closed, the dry well 3a can be flooded without accumulating water in the suppression chamber 3b. The amount of water can be reduced as compared with the case where the storage container 3 is entirely filled with water.
Therefore, according to the flooding method of the reactor containment vessel 3 of the present embodiment, the reactor containment vessel 3 is flooded while suppressing the amount of the filler 11 and water necessary for the flooding of the reactor containment vessel 3 as much as possible. Can do.

Moreover, according to the flooding method of the reactor containment vessel 3 of this embodiment, although the said filler supply path (supply piping 21) cannot be ensured with respect to the vent system containing the downcomer 5, the damaged location which becomes a cause of water leakage exists. When the filler 11 is limited to the suppression chamber 3b, and the filler 11 can be filled in the suppression chamber 3b, the filler 11 is placed in the suppression chamber 3b until the opening 5a of the downcomer 5 connected below the vent pipe 3c is closed. The opening 5a of the downcomer 5 is closed by supplying. As described above, the opening 5a of the downcomer 5 that connects the internal space of the suppression chamber 3b and the vent pipe 3c is closed, so that when the reactor containment vessel 3 is submerged, the inside of the suppression chamber 3b is passed through the vent pipe 3c. Water can be prevented from flowing into the water. According to the flooding method of the containment vessel 3 of this embodiment, the amount of the filler 11 is the amount from the bottom of the suppression chamber 3b to the height at which the opening 5a of the downcomer 5 is closed, and the torus. Compared to the case where all the chambers 2a are filled with the filler 11, the number of the chambers 2a can be extremely reduced. Further, according to the method of flooding the containment vessel 3 of the present embodiment, since the opening 5a of the downcomer 5 is closed, the dry well 3a can be flooded without accumulating water in the suppression chamber 3b. The amount of water can be reduced as compared with the case where all of the reactor containment vessel 3 is filled with water.
Therefore, according to the flooding method for the reactor containment vessel 3 of the present embodiment, the reactor containment vessel 3 can be flooded while suppressing the amount of the filler 11 and water necessary for flooding the reactor containment vessel as much as possible. it can. Even if there is a damaged portion in the suppression chamber 3b, the reactor containment vessel 3 can be flooded without specifying the location and repairing.

  Moreover, according to the flooding method of the reactor containment vessel 3 of the present embodiment, when the filler supply path (supply pipe 21) cannot be secured and the filler 11 cannot be filled in the suppression chamber 3b, the suppression chamber 3b. The torus chamber 2a is filled with the filler 11 and the torus chamber 2a is closed. By closing the torus chamber 2a in this way, even when the vent pipe 3c is damaged, it is possible to prevent water from leaking outside the suppression chamber 3b when the reactor containment vessel 3 is submerged. it can. According to the flooding method of the reactor containment vessel 3 of this embodiment, the amount of the filler 11 is the amount up to the height at which the connection portion between the vent pipe 3c and the suppression chamber 3b is embedded, and the torus chamber 2a Compared with the case where all are filled with the filler 11, the amount can be extremely reduced.

  Moreover, according to the flooding method of the reactor containment vessel 3 of the present embodiment, even if the vacuum breaker 8 disposed above the connection portion between the vent pipe 3c and the suppression chamber 3b is damaged, When the reactor containment vessel 3 is submerged, it is possible to prevent water from leaking outside the suppression chamber 3b. According to such a flooding method for each vessel 3 of the reactor according to the present embodiment, the amount of the filler 11 is up to the height at which the damaged portion of the vacuum breaker 8 is buried, and the torus chamber 2a is filled. Compared with the case of closing with the material 11, it can be extremely reduced.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the description of the present embodiment, the description of the same parts as those of the first embodiment is omitted or simplified.

  FIG. 11 is a flowchart for explaining the method of flooding the reactor containment vessel 3 of this embodiment. As shown in this figure, Step S1 to Step S3, Step S7 and Step S8 are the same as those in the first embodiment.

  In the flooding method for the containment vessel 3 of the present embodiment, when it is determined in step S3 that the filler 11 can be filled up to the lower end of the downcomer 5, the amount of filler 11 calculated based on the volume of the suppression chamber 3b is calculated. Is supplied into the suppression chamber 3b (step S30). That is, on the assumption that the lower part of the suppression chamber 3b is not damaged, the supply amount of the filler 11 exceeding the lower end of the downcomer 5 is calculated, and the calculated supply amount of the filler 11 is supplied to the suppression chamber 3b.

  Subsequently, it is confirmed whether or not the filler 11 has reached the lower end of the downcomer 5 (step S31). Here, for example, confirmation is performed by a CCD camera that can be remotely operated. In consideration of the possibility that the filler 11 has not spread evenly, it is desirable to check with a CCD camera at a plurality of locations. As a result, if the filler 11 has reached the lower end of the downcomer 5, the process proceeds to step S8 to fill the reactor containment vessel 3 with water.

  On the other hand, if the filler 11 has not reached the lower end of the downcomer 5 in step S21, it is estimated that the lower portion of the suppression chamber 3b is damaged. Therefore, the supply amount reaching the lower end of the downcomer 5 is calculated based on the volume of the suppression chamber 3b and the volume of the torus chamber 2a, and the filler 11 of this calculated supply amount is added to the suppression chamber 3b (including the torus chamber 2a). (Step S32). Note that the actual supply amount in step S32 is a difference from the amount calculated in step S30.

  Then, it is confirmed whether the filler 11 has reached the lower end of the downcomer 5 (step S33). Here, for example, confirmation is performed by a CCD camera that can be remotely operated. In consideration of the possibility that the filler 11 has not spread evenly, it is desirable to check with a CCD camera at a plurality of locations. As a result, if the filler 11 has reached the lower end of the downcomer 5, the process proceeds to step S8 to fill the reactor containment vessel 3 with water.

  On the other hand, if the filler 11 does not reach the lower end of the downcomer 5 in step S23, it is determined that the filler 11 cannot be filled up to the lower end of the downcomer 5 for some reason, and the process proceeds to step S7. The torus chamber 2a is filled with the filler 11. That is, if the filler 11 has not reached the lower end of the downcomer 5 in step S23, the determination in step S3 is denied and the process proceeds to step S7.

  According to the flooding method of the reactor containment vessel 3 of this embodiment, can the filler 11 be actually supplied to the suppression chamber 3b in steps S30 to S33 and the filler 11 can be stored in the suppression chamber 3b? Judging. For this reason, it is not necessary to confirm beforehand whether or not the lower portion of the suppression chamber 3b is damaged (step S4 in the first embodiment).

  In the flooding method for the reactor containment vessel 3 according to the present embodiment, it is determined whether or not the filler 11 can be filled in the suppression chamber 3b through Step S3 and Step 30 to Step S33, and the opening 5a of the downcomer 5 depending on conditions. Blocking is performed. That is, in the flooding method for the reactor containment vessel 3 of the present embodiment, Step S3 and Steps 30 to S33 correspond to the filling confirmation process and the downcomer blockage process of the present invention.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the spirit of the present invention.

  1 ... MARK-I type boiling water reactor, 2 ... reactor building, 2a ... torus room, 2b ... upper floor room, 3 ... reactor containment vessel, 3a ... dry well, 3b ... ... suppression chamber, 3c ... vent pipe, 4 ... vent header, 5 ... downcomer, 6 ... support, 7 ... reactor pressure vessel, 10 ... backup material, 11 ... filler, 21 ... Supply piping (filler supply route)

Claims (4)

A dry well that houses the reactor pressure vessel, a suppression chamber provided around the dry well, and a vent pipe that connects the dry well and the suppression chamber, at least of the suppression chamber and the vent pipe A method of flooding a reactor containment vessel having a damaged part that causes water leakage in either
A path determination step for determining whether a waterstop material supply path for supplying the waterstop material to the vent pipe can be secured;
A vent pipe closing step of filling the water stop material in the vent pipe when it is determined that the water stop material supply path can be secured in the path determination step;
After the vent duct obstruction process, we have lines for supplying water supplying step water to the reactor container,
In the route determination step, the water-stop material supply route is connected to a route connecting an upper floor chamber located above the torus chamber in which the suppression chamber is disposed and a midway portion of the vent pipe located inside the torus chamber. A method of flooding a containment vessel characterized in that it is determined that the water-stopping material supply path can be secured when there is no equipment that interferes with and cannot be removed . A downcomer is provided that is connected to the lower side of the vent pipe and connects the inner space of the suppression chamber and the vent pipe,
A filling confirmation step for determining whether or not the water stop material can be filled in the suppression chamber when it is determined that the water stop material supply route cannot be secured in the route determination step;
A downcomer blockage step of filling the suppression chamber with the waterstop material until the downcomer opening is closed when it is determined in the filling confirmation step that the waterstop material can be filled into the suppression chamber. And
There line the water supplying step after the downcomer blocking step,
In the filling confirmation step,
Check if there is a damaged part in the connection part between the vent pipe and the dry well by photographing, and if there is no damaged part and if there is a damaged part where the filler leaks in the lower part of the suppression chamber, 2. The method of submerging a reactor containment vessel according to claim 1 , wherein it is determined that the water stop material can be filled in the suppression chamber when there is no damaged portion that leaks . A torus chamber is provided in which the suppression chamber is installed;
A torus that fills the torus chamber with the water stop material up to the height of the connection portion between the suppression chamber and the vent pipe when it is determined that the water stop material cannot be filled into the suppression chamber in the filling confirmation step. A chamber closing process,
The method for flooding a containment vessel according to claim 2, wherein the water supply step is performed after the torus chamber closing step. A vacuum breaker for connecting the suppression chamber and the vent pipe is provided,
4. The nuclear reactor according to claim 3, wherein when a breakage point is confirmed in the vacuum breaker, the waterstop material is filled up to a height of the breakage point of the vacuum breaker in the torus chamber closing step. Containment container flooding method.

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